Drill shank and chuck assembly for a drill press

ABSTRACT

A drill shank and chuck assembly adapted for use in a drill press or the like and embodying an adapter collet which, by a detent action, enables drill substitution to be effected without drill press adjustment.

[ Aug. 21, 1973 United States Patent [1 1 Miller References Cited UNITED STATES PATENTS DRILL SHANK AND CHUCK ASSEMBLY FOR A DRILL PRESS [75] Inventor: Harold C. Miller, Chicago, Ill.

Clark Haffey [22] Filed:

Primary Examiner-Gil Weidenfeld Attorney-Norman H. Gerlach [57] ABSTRACT A drill shank and chuck assembly adapted for use in a 2; B23! i ig gg drill press or the like and embodying an adapter collet e1 80 9ieazrc 9l/ 7 '79 1 A which, by a detent action, enables drill substitution to 0 l5 79/2 be effected without drill press adjustment.

1 Claim, 5 Drawing Figures DRILL SHANK AND CHUCK ASSEMBLY FOR A DRILL PRESS The improved drill shank and chuck assembly comprising the present invention is designed for use primarily in connection with the operative installation of a diamond core drill into the chuck of a drill press, and also the removal of such core drill from the chuck. The invention is, however, not necessarily limited to such use, and shank and chuck assemblies embodying the present invention may, if desired and with substantially no modification, be employed in connection with a wide variety of rotary machine tools having shank portions which are to be rotatively driven and have holding chucks associated therewith, regardless of whether such chucks constitute the output driving elements of drill presses or of a wide variety of metal working machines such, for example, as lathes, boringmachines, etc., too numerous to mention.

Heretofore, it has been common practice to connect a core drill to the chuck of a drill press or the like by way of a split collet which is associated with and forms a part of the chuck and into which the shank of the core drill is introduced. A bonnet nut which is threadedly received on the collet functions, when tightened, to shrink or contract the collet legs in centripetal fashion about the drill shank, and the relatively high grasping pressure of the collet legs is relied upon as a frictional drive for imparting torque to the core drill from the chuck. Core drill substitution is effected by loosening the bonnet nut in order to release the collet legs so that they automatically expand or spread apart, after which the drill shank may be withdrawn from the collet, the shank of a different core drill inserted into the expanded collet, and the bonnet nut again tightened for collet contracting purposes. With such a procedure, numerous manual operations often requiring the use of a tool, such as a torque wrench, are required. Furthermore, certain functional limitations are present as, for example, drill slippage when insufficient tightening torque is applied to the bonnet nut in order to secure the shank of the core drill in the collet. Additionally, it frequently happens that when the bonnet nut is loosened for drill shank removal purposes, the core drill will fall by gravity from the chuck with resultant break age, unless, of course, provision is made for holding the core drill during such loosening of the nut. Still further, occasions arise where undue tightening of the bonnet nut on the collet results in damage to the core drill shank as, for example, where the collet legs create small indentations or burrs on the sides of the shank so that, after repeated use, the shank will not fit accurately into the bore of the collect. Another functional limitation is that the bonnet nut is sometimes difficult to grasp for manipulating purposes, especially in a drill press having a multiplicity of closely positioned drillretaining chucks.

The present invention is designed to overcome the above-noted limitations that are attendant upon the use of a conventional chuck of the split collet type and, toward this end, the invention contemplates the provision of a novel chuck assembly which, for its proper operation, requires a slight modification of the associated core drill shank and, when such modification is made, will enable the core drill shank to be manually pushed into the chuck assembly and become latched therein by a detent action, while at the same time a positive torque drive is automatically established without danger or the possibility of slippage between the core drill shank for purposes of core drill substitution is accomplished by manually pulling the core drill shank from the chuck assembly. The installation of the core drill shank in the chuck assembly and its removal therefrom is accomplished without necessitating the performance of any operation whatsoever upon the drill press or the latters chuck assembly, the insertion of the shank being complete as soon as the detent action takes place and removal of the shank being one of manual withdrawal as soon as the detent action has been released.

Incarrying out the invention, the conventional split collet which invariably is associated with the chuck of a drill press is removed and, in its place, a novel solid wall collet is substituted, the latter collet fitting snugly into the tapered socket in the drive spindle which formerly received the split collet. A bonnet'nut which is threaded onto the solid wall collet functions, not to shrink the collet as heretofore used, but permanently to hold the solid wall collet in position within the spindle socket. The bonnet nut, once applied, is permanently fastened in position against removal.

With the chuck thus permanently installed in the associated drill press, no further drill press manipulations are required and core drillsubstitution is accomplished by thesimple expedient of pulling the shank of an existing installed core drill axially from the collet by the use of manual force and the pushing of a different drill shank into such collet. When the core drill shank is pushed into the collet to its home position, a drive pin which is fixedly secured to the solid wall collet projects into a recess which is provided in the drill shank and automatically furnishes the necessary torque for driving purposes. At the same time, an O-ring which is carried internally of the collet snaps into a latching position within an annular recess which is formed in the drill shank and holds the shank against falling out of the chuck until it is manually pulled therefrom as previously set forth. These functional elements, i.e., the torque drive means and the detent means, are so designed that they in no way interfere with the normal flow of coolant fluid from the central bore of the drive spindle through the core drill shank to the cutting annulus on the lower end region of the core drill.

The provision of a drill shank and chuck assembly such as has briefly been outlined above and possessing the stated advantages constitutes the principal object of the present invention. Numerous other objects and advantages of the invention, not at this time enumerated, will readily suggest themselves as the nature of the invention is better understood from a consideration of the following detailed description.

The invention consists in the several novel features which are hereinafter set forth and are more particularly defined by the claims at the conclusion hereof.

In the accompanying single sheet of drawings forming a part of this specification, one illustrative embodiment of the invention is shown.

In these drawings:

FIG. 1 is a fragmentary sectional view taken substantially centrally and longitudinally through a drill shank and chuck assembly embodying the principles of the present invention, certain parts being shown in elevation in the interests of clarity;

FIG. 2 is a transverse sectional view taken on the line 2-2 of FIG. 1;

FIG. 3 is a transverse sectional view taken on the line 33 of FIG. 1;

FIG. 4 is a transverse sectional view taken on the line 44 of FIG. 1; and

FIG. 5 is a fragmentary side elevational view of the core drill shank which is employed in connection with the invention.

Referring now to the drawings in detail, the present drill shank and chuck assembly is illustrated herein for exemplary purposes as being operatively applied to a normally vertically extending core drill of the type which ordinarily is applied to the chuck of a. conventional drill press and is commonly referred to as a tube drill for the reason that it comprises a tubular, thin walled, seamless, metal tube or shank 12. The latter has fixedly connected to its lower end a diamondimpregnated cutting annulus 14, the lower end or rim of which is adapted to engage a ceramic or other workpiece which is to be drilled. Ordinarily, the upper end of the shank 12 of the core drill 10 is adapted in a split collet type chuck in such a manner that the central longitudinal bore 16 which extends through said shank l2 registers in sealing relationship with a hollow tubular spindle so that a suitable coolant such as water may be fed through the tubular shank 12 to the cutting annulus 14.

The present invention, as previously described, is designed to obviate the difficulties which are encountered in applying such a core drill to a conventional split collet type chuck and in removing the drill from the chuck and which ordinarily involve holding the drill with one hand and loosening or tightening the collet by turning the bonnet nut for the collet with the other hand. Accordingly, and as will be described in detail presently, a special type of collet is employed in connection with the drill press chuck while the shank of the core drill is modified accordingly.

The assembled chuck and drill constituting the present invention are illustrated in FIG. 1, and except for the substitution of the novel collet arrangement of the present invention, together with a slight modification of the shank 12 of the core drill 10, no appreciable modification of the drill press housing, the chuck, the spindle, or the rotatable mounting means for the spindle within the housing is required.

The drill press which is illustrated herein is purely conventional and no claim is made herein to any novelty associated with the same, the novelty of the present invention residing solely in the nature of the aforementioned collet which is used with the drill press chuck for operatively holding the core drill 10 during cutting or drilling operations. The drill press is shown in a fragmentary manner and is designated in its entirety by teh reference numeral 20, the disclosure including the outer fixed drill press housing 22, the iner vertically slidable quill 24, the lower ball bearing 26, and the drill press drive spindle 28.

Only the lower region of the spindle 28 is disclosed herein, it being understood that the upper portion of such spindle is splined in the usual manner to receive a driving pulley thereover from which the spindle derives its rotary motion. Additionally, conventional means are provided whereby vertical motion may be applied to the quill 24 to effect up and down sliding motion thereof within the outer'shell 22 under the control of a hand wheel or lever (not shown).

The spindle 28 of the drill 20 is tubular and provides a central longitudinal passage 30 by means of which the coolant fluid, which may be water, is fed to the bore 16 in the shank 12 of the core drill 10. The lower region of the spindle 28 is formed with an enlarged section 32 which establishes an upwardly facing shoulder 34. The latter provides a seat for the inner race of the all bearing 26, and such inner race is clamped against such seat by means of a clamping nut 36 which is received over a threaded section 38 on the spindle 28. A lock nut 40 maintains the nut 36 in its tightened condition. Immediately'below the ball bearing 26 is a conventional lip seal 42 which is held in position between the non-rotatable quill 24 and the rotatable spindle 28 by means of a split snap-ring 44 which seats within an annular groove 46 in the lower rim region of the quill 24.

The spindle 28 is provided with the usual colletreceiving socket 48, the latter being upwardly tapered on a relatively small slant angle and the wall 50 of such socket being exteriorly threaded as indicated at 52 for reception thereover of a bonnet nut 54 having a stepped bore 55. The bonnet nut has an internal annular shoulder 56 by means of which a conventional split collet (not shown)is forced upwardly into the tapered socket 48 when the bonnet nut is tightened against the collet.

Considering now the nature of the diamondimpregnatedcutting annulus 14, this annulus is preferably of the general type which is shown and described in U. S. Pat. No. 2,995,161, granted to me on Aug. I5, I96] and entitled ABRASIVE DIAMOND CORE DRILL. For a full description of the nature and operation of such annulus, reference may be had to such patent. However, for descriptive purposes herein, it is deemed sufficient to state that the annulus is disposed adjacent to the lower rim of an enlarged cylindrical drilling head 60 which is formed on the lower end of the shank 12, the head being provided with an internal socket 62 which is in communication with the coolantreceiving bore 16 in the shank 12. The outer surface of the enlarged head 60 is provided with a plurality of circumferentially spaced vertical grooves 64 which interrupt the continuity of the cutting annulus l4 and serve the purpose of low friction paths for the flow of coolant fluid upwardly and out of the hole which is being drilled in the workpiece, all in a manner that has clearly been set forth in the specification of aforementioned US. Pat. No. 2,995,16l. The particular core drill l0, insofar as it has previously been described herein, is thus of conventional construction, the only difference between such core drill and the core drill of the aforementioned patent being in the provision of a relief area in the form of a notch 66 (see FIGS. 1 and 3) which is provided in the wall of the shank 12 at the extreme upper end of the latter, and the function of which will be set forth subsequently. Similarly, the drill press 20, insofar as it has previously been described herein, likewise is of conventional construction. The essential novelty of the present invention resides solely in the provision of a novel drill press chuck assembly 68 embodying a special collet such as is designated by the reference numeral 70, such special collet being in the nature of a substitute for the conventional split collet which ordinarily is disposed with a taper fit within the tapered bore 48 of the tubular spindle 28 of the drill press 20. The invention also involves the manner with which this special frustoconical collet 70 cooperates with the notched shank 12 of the core drill 10.

Considering now the nature of the special collet 70, this collet is of solid tubular construction (as distinguished from the usual longitudinally split collet) and is provided with an outer frusto-conical wall surface 72 which has a taper or slant angle commensurate with the slant angle of the upwardly tapered socket 48 in the spindle 28 so that, when the collet 70 is forced upwardly into such socket, it will attain a tight taper fit. The lower end region of the collet 70 is provided with a downwardly facing annular shoulder 74 which seats on the aforementioned shoulder 56 of the internally threaded bonnet nut 54.

The bonnet nut 54 is provided with a small diameter transverse bore 77 which intersects the stepped bore 55 in tangential fashion. An annular groove 75 extends around the lower region of the collet 70 and a pin 76 which is driven through the bore 77 passes tangentially through the groove 75 and locks the bonnet nut 54 in its tightened position wherein the shoulder 74, by reason of its engagement with the shoulder 56, forces the collet bodily upwardly into tight-fitting relation with respect to the collet-receiving socket 48.

The collet 70 has formed therein a relatively deep cylindrical socket-forming bore 78, the latter communicating with a reduced counterbore 80 which extends through the upper inwardly extending circular wall portion 82 of the collet 70 at a point above the socket 78. The bore 80, in turn, communicates with the bore 30 in the spindle 28. An offset or eccentric vertically extending bore 84 (see FIG. 2) is provided in the upper wall portion 82 alongside the bore 80 and receives therein with a press fit a vertically disposed downwardly projecting drive pin 86. The latter projects into the notch 66 in the upper end of the core drill shank 12 when the latter is in its proper position with the collet 70.

In the lower region of the collet 70 and in the vicinity of the annular groove 75, there is provided a relatively deep internal annular groove 88 within which there is permanently disposed a detent element in the form of an elastomeric O-ring 90. This O-ring is designed for cooperation with a relatively shallow annular detent recess 92 (see FIG. 5) having diverging side walls and which is provided in the medial region of the core drill shank 12 for releasably maintaining the core drill in position within the drill press in a manner that will be set forth presently.

It will be understood that in practicing the invention, the conventional drill press 20 is initially conditioned for quick and easy application of the core drill l0 thereto and similar removal of the core drill therefrom. This is accomplished by removing the conventional split collet arrangement which ordinarily is disposed in the collet-receiving socket 48 of the spindle 28 and substituting therefor the solid wall collet 70. After such substitution, the bonnet nut 54 is tightened on the spindle with the locking pin 76 in place within the groove 75. This results in completion of the drill press conversion and there is no further need for manipulating the bonnet nut 54 during core drill application to or removal from the drill press 20.

As previously stated, core drill application to the chuck assembly 68 of the drill press 20 is accomplished by the simple expedient of aligning the shank 12 with the cylindrical bore or socket 78 in the solid wall collet and then forcing the core drill bodily upwardly so that the shank l2 enters such socket. During such insertion of the shank 12 into the socket 78, no thought need be given to the angular or rotational disposition of the shank. If the notch 66 in the upper end of the shank l2 happens to be aligned vertically with the drive pin 86, then the shank will move upwardly to its home position within the collet 70 and the drive pin 86 will enter the notch 66 in driving relationship. If, on the other hand, at the time of introduction of the shank 12 into the bore or socket 78, the notch 66 is not in vertical alignment with the drive pin 86, the upper rim of the core drill shank 12 will strike against the lower end of the drive pin 86 and, then the operator may rotate the core drill 10 bodily about its longitudinal axis, while the at the same time continuing to apply upward thrust to the drill until the drive pin 86 and the notch 66 move into alignment, whereupon the core drill shank 12 will move upwardly to its home position and the O-ring 90 will function as a detent member by entering the annular groove 92 (see FIG. 5) in the medial region of the core drill shank 12, thus releasably latching the core drill 10 in its home position. The drill press 20 with the core drill 10 thus installed therein is then ready to be set into operation for cutting purposes.

During actual cutting operations on a workpiece, the drive pin 86 which projects into the notch 66 in the upper end of the drill shank 12 supplies the necessary torque to the core drill 10 for effecting cutting operations.

Removal of the core drill 10 from the drill press 20 is accomplished by merely pulling the former from the latter in a downward direction, thus overcoming the detent action of the elastomeric O-ring 90 which remains within the groove 88 during such withdrawal of the shank 12 from the collet 70 by reason of the relatively shallow depth and sloping side walls of the detent recess 92.

The invention is not to be limited to the exact arrangement of parts shown in the accompanying drawings or described in this specification as various changes in the details of construction may be resorted to without departing from the spirit or scope of the invention. Therefore, only insofar as the invention is particularly pointed out in the accompanying claim is the same to be-limited.

Having thus described the invention what I claim as new and desire to secure by letters patent is:

1. In a machine tool, a rotary drive spindle having a tapered collet-receiving socket in its forward end, a tubular frusto-conical collet disposed within said socket with a taper fit and projecting forwardly therefrom, the projecting portion of said collet being provided with an external annular groove therearound and with a forwardly facing annular shoulder forwardly of the groove, the forward end of the spindle being exteriorly threaded, a bonnet nut threadedly received on said spindle and having a stepped axial bore defining a rearwardly facing annular shoulder which bears against the forwardly facing shoulder on the projecting portion of the collet and serves to force the latter inwardly of the socket in tight fitting relationship when the bonnet nut is tightened, said bonnet nut being provided with a transverse bore which intersects both the stepped axial bore in the bonnet nut and the external annular groove in the projecting portion of the collet, a locking pin projecting through said transverse bore and serving to lock the bonnet nut in its tightened position, said collet being formed with a relatively deep central axial socket-forming bore therein defining a circular wall portion at the rear end of the collet and which is provided with a reduced counterbore therethrough, the forward end region of said socket-forming bore being provided with a relatively deep internal annular detent groove therearound, an elastomeric O-ring seated within said detent groove, a cylindrical tool-carrying shank adapted for endwise projection into said bore to a home position in the collet, the medial region of said shank being formed with a relatively shallow detent recess having outwardly sloping side walls, said relatively deep groove and relatively shallow recess being disposed in register with each other when the shank is in its home position within the bore, said groove in the bore of the collet, recess in the shank, and O-ring constituting detent means for releasably maintaining the shank within the collet, said circular wall portion at the rear end of the collet being provided with an eccentrically disposed bore, and a drive pin disposed within said latter bore with a press fit and projecting forwardly into said socket-forming bore, the rear end of said shank being formed with an eccentrically disposed notch which is received over said drive pin when the shank is in its home position within the collet. 

1. In a machine tool, a rotary drive spindle having a tapered collet-receiving socket in its forward end, a tubular frustoconical collet disposed within said socket with a taper fit and projecting forwardly therefrom, the projecting portion of said collet being provided with an external annular groove therearound and with a forwardly facing annular shoulder forwardly of the groove, the forward end of the spindle being exteriorly threaded, a bonnet nut threadedly received on said spindle and having a stepped axial bore defining a rearwardly facing annular shoulder which bears against the forwardly facing shoulder on the projecting portion of the collet and serves to force the latter inwardly of the socket in tight fitting relationship when the bonnet nut is tightened, said bonnet nut being provided with a transverse bore which intersects both the stepped axial bore in the bonnet nut and the external annular groove in the projecting portion of the collet, a locking pin projecting through said transverse bore and serving to lock the bonnet nut in its tightened position, said collet being formed with a relatively deep central axial socket-forming bore therein defining a circular wall portion at the rear end of the collet and which is provided with a reduced counterbore therethrough, the forward end region of said socket-forming bore being provided with a relatively deep internal annular detent groove therearound, an elastomeric O-ring seated within said detent groove, a cylindrical tool-carrying shank adapted for endwise projection into said bore to a home position in the collet, the medial region of said shank being formed with a relatively shallow detent recess having outwardly sloping side walls, said relatively deep groove and relatively shallow recess being disposed in register with each other when the shank is in its home position within the bore, said groove in the bore of the collet, recess in the shank, and O-ring constituting detent means for releasably maintaining the shank within the collet, said circular wall portion at the rear end of the collet being provided with an eccentrically disposed bore, and a drive pin disposed within said latter bore with a press fit and projecting forwardly into said socket-forming bore, the rear end of said shank being formed with an eccentrically disposed notch which is received over said drive pin when the shank is in its home position within the collet. 